Elastic-fluid turbine.



PATENTED JUNE 5, 1906.

J. WILKINSON. ELASTIC FLUID TURBINE.

APPLICATION FILED JUNBZS, 1905.

.6. damas Br 7 Mfr WIT/VESSES: 4M f@ Awith the luids increase in volume.

UNITED STATES PATENT 'oEEioE.

JAMES WILKINSON, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO WIL- KINSONTURBINE COMPANY, A CORPORATION OF ALABAMA.

Specification of Letters Patent.

' '.-atenteci June 5, 1906.

Application led June 23, 1905. Serial No. 266,650.

bines operating by stage expansion of the motor fluid to convert itfractionally into vis viva, which is abstracted by sets of rotatablebuckets disposed within the stage-compartments.

In turbines of this general-type as the fluid flows from stage to stageand acts succes- .sively against the rotatab e buckets therein it.increases in volume as it drops in pressure.

This necessitates the provision of a working passage for the iiuid whichincreases in crosssectional area across stages in accordance Thisworking passage comprises nozzle-passages for the fluid betweenstages,which.succes sively increase in cross-sectional area, thesenozzle-passages being formed in or leading through the division wall orwalls between stages which may be considered here as diaphragms. One ofthe most important points to be considered in designing a turbine ofthis type is the cross-sectional area of the last row or rows ofnozzle-passages relative to the available cross-sectional area of thepassage at the admission side of the diaphragm, since they will fix thecross-sectional area of the irst and other rows of nozzles7 which are ofa definite proportion to the last row and determine the total capacityor power of the turbine. For this reason it is important that thecapacity of the last row of nozzles should be as large as is consistentwith maintaini the proper strength in the diaphragm through which theylead, as this diaphragm must e designed to preserve the strength andstiiness requisite to withstand the pressure to which it is or may besubjected.

The object of my present invention is to design a turbine which willpossess the greatest possible nozzle capacity consistent with properstrength in the diaphragm.

It will be evident that the area of the nozzle-supply openings in thelast diaphragm should be as large as its strengthwill permit to producethe maximum nozzle capacity for ther.-f

opening in the diaphragms.

last sta e. In practice the diaphragme lare provide with webs or armsbetween the several nozzies, which must possess sufficient strength towithstand the pressure-load on lthe diaphra m. Where the diaphra m mustbe provide with nozzles calculate to pass the fluid in an expandedcondition, the problem of preserving the stiffness of the diaphragm andat the same time discharging the fluid with the highest efiiciencagainst the succeeding buckets becomes ofy vital importance.Thenozzle-supply openings being larger in cross-sectional area than thenozzles become the determining factor in design.

It will be evident that the diaphragm-passages must be enlarged eithercircumferentially or radially to increase their capacity. When elongatedcircumferentially, the increase in their-proportions is limited by thenecessity of preser the necessary width of .supporting-webs. heir radialenlar ement is also limited by the practicable buc et length and thedisadvantages attendant u on theuse oflongbuckets. Thesetwo metho ofenlarging the working passage lare now commonly practiced and carried tothe maximum extent consistent with safety and eficiency According to myinvention, taking this maximum nozzle-supply area or capacity as axedquantity, the available cross-sectional area and the capacity of thenozzles proper may be further increased relatively thereto withoutaffecting the strength of the diaphragm byincreasing thea le ofinclination of the nozzles. It must be reily evident that thecross-sectional area of two parallel nozzles leading at different anglesfrom the same supply-opening will be different, the area increasing asthe nozzle-a le approaches ninety deIgIrees to the plane o the bucketsrotation. ere, then, we find a purely mechanical condition by whichwithout sacrifice of diaphragm strength or large increase of bucketlength and wheel diameter the nozzle capacity may be materiallyincreased relatively to a fixed maximum supply area or capacity. It istherefore an important object of my invention' to provide a turbinehaving pressureloaded diaphragms or equivalents with nozzle-passages ofrelatively increasing angular inclination toward its discharge end,whereby I am enabled to pass a maximum volume .of fluid with a minimumbowl or supply- IOO The inclination of the'nozzles and the curvature ofthe buckets have a fixed relationship which must be provided for indesigning a turbine where the angles of nozzle inclination vary, and itmay be roughly stated that the angle of the buckets receiving edges totheir plane of rotation should increase in proportion with the nozzleangle, while the curvature or depth of the buckets should decrease. Itherefore propose to provide the turbine above described with rows ofbuckots having increasing angles and decreasing concavity toward thelow-pressure end of the turbinefit being assumed that the lowereiiicioncy at which the fluid will act upon buckets of less depth andcurvature will be comwnsated by reducing the fan action of the longbuckets, which would otherwise be neccssary in the low-presssure stageor stages.

Briefly stated, it is my object to increase the angle of both nozzlesand buckets proportionately to enable a maximum amount of fluid to passwith as small loss as possible through a minimum opening or workingpassage in a diaphragm or division wall or Walls betweenstage-compartments.

AS illustrative of the principles governing turbine construction andpertinent to the conditions which control vthe designing of a machineinaccordance with my present invention, I make reference to theaccompanyin" drawings, in which- A Figure 1 is a vertical sectional viewthrough the working passage of a multistage turbine in which there is asuccessive increase in the degree of nozzle inclination and bucketangle, while there is a successive decrease in the bucket concavity orcurvature and depth. Fig. 2 is a partial vertical section through one ofthe working passages, Fig. 1. Fig. 3 illustrates the construction of anozzle-passage in the last diaphragm, Fig. 1, when the nozzle has aninclination of twenty degrees. Fig. 4 is a section through Fig. 3, whichby comparison with Fig. 2 illustrates the increased radial dimensions ofboth nozzle and bucket requisite to pass the same amount of iiuid asflows through the last nozzle in Fig. 2. 5 illustrates thecircumferential elongation of the nozzle-passage in Fi 3 requisite topass the same volume of uid when the nozzle and bucket correspond inradial dimensions with the last nozzle and bucket illustrated in Fig. 2.Fig. 6 is a sectional view through Fig. 5. Figs. 7 and 8 are enlargedviews of nozzle-passages, illustrating more clearly the relation betweenthe cross-sectional areas of the nozzles proper and theirsupply-openings for different anales of nozzle inclination. This viewalso illustrates the variation in bucket angles and concavity. Fig. 9 isa partial plan view of a diaphragm, illustrating one of the webs or armswhich support the pressure-load on the diaphragm and determine itsstrength.

Similar reference-numerals refer to similar parts throughout thedrawings.

I have illustrated my invention embodied in a multistage turbinecomprising a plurality of diaphragm-partitions 1, 2,'3, and 4, whichsubdivide the turbine into Wheel-compartments within which the' wheels 5rotate. These wheels are keyed to a shaft (not shown) and carryconcavo-convex buckets, which cooperate with nozzle-passages leading atan incline through the dia hragms.

The diaphragms may form t e exterior casing or may be connected to anouter shell or retained in relative position in any desired manner. Alsofluid-pressure may be supplied to the initial set of nozzles in anydesired manner, none being here shown, as the same forms no part of mypresent invention. The nozzles 6, 7, 8, and 9, wlnch respectively leadthrough the successive diaphragms 1, 2, 3 and 4, respectively coperatewith sets of buckets 10, 11, 12, and 13, carried by the wheels 5. Forthe purpose of illustrating the principles governing the improved designof this turbine I illustrate these nozzles as of the parallel type anddisposed at successi-vely-increasing angles to the plane of rotation oftheir respective buckets. Thus the nozzles 6, of which there may beseveral suc'- cessive rows of the same size and inclination, areinclined at an angle of twenty degrees, the nozzles 7 at an angleoftwenty-ve degrees, the nozzles 8 at an angle of thirty degrees, andthe nozzles 9 at an angle of thirty-five degrees. As the nozzlesincrease in circumferential proportions they are provided with guides14, secured therein in any desired manner and subdividing the nozzleinto parallel passages for the motor fluid. Using the term bowl todesignate enerally the enlarged supply end from w `ch the nozzles properlead, it will be noted readily that the cross-sectional areas of thebowls or supplyopenings differv from that of the nozzles. Thus takingthe areas of the nozzles proper as a base and giving it a rating of onehun dred per cent. opening, the relative rating of the supply-openingfor the nozzle-when at an angle of twenty degrees will be substantiallythree hundred per cent., when at an incline of twenty-five degreessubstantially two hundred and fifty per cent., when at an incline ofthirty degrees substantially two hundred per cent., and when at anincline of thirtyive degrees substantially one hundred and seventy-fiveper cent. Figs. 7 and 8 more clearly illustrate these extremes, thenozzles there shown being of equal cross-sectional area and capacity,whereas the relative area of the supply-opening for the nozzle having aninclination of twenty degrees is nearly twice as large as that of thenozzle having an inclination of thirty-five degrees. From this itfollows that the greater the angle of nozz'le inclination the lessamount of IOO IIO

www*

metal 1t is necessary to'cut out' of the diaphragm to pass equal volumesof fluid therethrough. The value of the application of this principle ofdesign to aturbine is evident when We consider the importance ofproviding the last diaphragms With a maximum nozzle-opening consistentWith preserving their strength, for by increasing the angle of nozzleinclination, as shown in Fig. 1, the undesirable results which Wouldfollow from the use of nozzles of the same inclination, as illustratedin Figs. 3 and 6, are largely avoided. Referring to the nozzle-passage 9in the last diaphragm, by increasing its angle of inclination fromtwenty to thirty-five degrees I am enabled to reduce the cross-sectionalarea of the supply-opening approximately fortyper cent. and atthe sametime to shorten the radial length of the buckets approximately fifty percent. I thus avoid not only Weakening the diaphragm, but also increasingthe diameter of the bucket-Wheels due to the elongation of the buckets,which Would require a corresponding increase in the dimensions of thediaphragm and outer casing of the turbine. This latter point isillustrated by the comparison of Fig. 4 with Fig. 2, the nozzle 9a,diaphragm 4a, and buckets 13"L being designed for dimensions which Wouldbe requisite if substituted for the last diaphragm 4 and buckets 13 inFig. 2. If this change in wheel diameter is to be avoided, it can onlybe done Without my invention, as shoWn in Figs. 5 and 6, Where thecircumferential elongation of the nozzle 9b Will reduce the number ofWebs or arms 15, and as a certain number of these are requisite toinsure the stiffness of the diaphragm'the nozzle capacity must besacrificed to provide for them.

Without further elaborating the advantages attendant upon the use of thenozzles of varyin inclination I pass on to a consideration of tIiedesign of the buckets calculated to cooperate at highest efficiency Withthe several sets of nozzles. The angle of inclination of the nozzle isthe determining factor controllin the angle of the buckets receivingedges to ille jet of fluid and also the maximum concavity which thebuckets impactsurface may have. The increase in the angles of thenozzles in the last diaphragm or diaphragms Will necessitate an increasein the angles of the buckets receivin edges and a decrease of itsconcavity. In i s. 7 and 8 I have illustrated the changes in ucketconformation attendant upon a change of fifteen degrees in nozzleinclination. It Will be understood that the angles and conformation ofthe buckets may be varied from the disclosure, that shown beingapproximately estimated as the most efficient design for cooperatingwith the nozzles at the indicatedy angles. n

In the drawings .and preceding specification I have illustrated anddescribed one form of turbine embodying my invention. This is done incompliance with the requirements of the patent law and not with a viewto limiting myself either to the angles given or the construction shown,the invention being of such a character that it may be varied With thedesign of each turbine and may be applied to any of the forms of turbinenoW in use, Whether the stage-comparments be formed in the same orseparate shells o Whether substantially the equivalent of diaphragms beused.

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is-

1. An elastic-fluid turbine operating by stage expansion and having aWorking passage Wliich enlarges across sta es, the provision therein ofsuccessive'nozz es formed in stationary elements and disposed atincreasing angles across stages to the plane of bucket rotation, andbuckets of decreasing concavity cooperating With said nozzles.

2. In a multi p le-stage turbine, buckets rotatable Within t e severalstages, and nozzlepassages discharging fluid-pressure against saidbuckets, the nozzle-passages for supplying motor fluid to thelow-pressure stage or stages having a greater angle of inclination thanthe nozzles for the other stage or stages, substantially as and for thepurposes described.

3. In a multiple-stage turbine, buckets rotatable Within the severalstages, nozzle-passages dischargingfluid-pressure against said buckets,the nozzle-passages forthe 10W- pressure stage or stages having a eaterangle of inclination than the nozz es for the other stages, and thebuckets co erating with said nozzle-passages having erent angles ofinclination, substantia ly as described.

4. In a multiple-stage turbine, stationary elements between the4stage-compartments, nozzle-passages leadin through said elements andforming con uits for the fluid between stages, said nozzles-havingrelatively smaller induction ends, as roportioned to the cross-sectionalarea of t e nozzles, and relatively larger angles of inclination, forthe low-pressure stages than for the high-pressure stages.

5. In a multiple-stage turbine, partitions between stages andnozzle-passages leadin through said partitions and having enlargeadmission-openings and angularly-disposed discharge-passages leadingtherefrom and constituting the nozzles roper, the crosssectional area ofthe nozz es roper for the last stages being increased re atively to thecross-sectional area of their admission-openin s.

g. In a turbine operating by stage expansion, nozzle-passages formed instationary elements through which the motor fiuid flows IOO IIO

in succession to act against rotatable buckets, and supply-openings forthe nozzles, the cross-sectional area of said openin s representing adecreasing percentage of t 1e crosssectional 'area of their respectivenozzles for the last stage as compared with the preceding stages.

7. In a multiple-stage turbine, fluid-supply nozzleassages comprisingenlarged admissionen sand nozzles roperleadingtherefrom, thecross-sectionalparea of the nozzles proper for the last stage or stagesbeing increased relatively to the cross-sectional area of theiradmission ends by increasing their angle of inclination to the rotatingbuckets against which they discharge fluid.

8. In an elastic-Huid turbine subdivided into stages by diaphragms,nozzle-supply openings formed in said diaphragms and JAMES WILKINSON.

Witnesses M. FREEMAN CooRoFT, A. BRINTNALL TINGLEY.

